1. Technical Field
The present disclosure generally relates to cooling integrated circuits.
2. Description of the Related Art
Semiconductor circuits that are subjected to undesirable quantities of thermal energy may operate differently than designed, may malfunction, or may fail. As a result, the distribution of thermal energy in a circuit can be of great interest to a manufacturer.
Heat is thermal energy in the process of transfer or conversion across a boundary of one region of matter to another. Thermal energy is the total amount of kinetic energy in a substance, whereas temperature is a measure of the average of kinetic energy in the substance. In heat transfer, conduction is the transfer of thermal energy in a substance due to a temperature gradient. Heat transfer always goes from a region of higher temperature to a region of lower temperature, and acts to equalize the temperature difference.
One source of heat in a system is power dissipation. The power dissipated in a resistor can be calculated as function of the resistance of the resistor and the current flowing thought the resistor, i.e., P=I2R. The power dissipated in a resistor goes into heating the resistor; this is known as Joule heating. Because any circuit component having a resistance and current flowing through it will dissipate power and result in Joule heating, many circuits must take heating issues into consideration.
Several popular methods of channeling heat at the package level exist, but many of them consume power in the process. Examples, include thermoelectric cooling, integrated micro pumps inside the silicon substrate below the high power region of integrated circuits, fluid-based cooling of hot regions of integrated circuits, and heat sink-based cooling from the casing of integrated circuits.